Rebuilt Engine Too Tight For Starter Motor

[HRthirtyone]

Just got the rb20 a new crank, main and big end bearings. The crank was measured at an engine shop, and the correct grade bearings were then installed going by the crank size.

Just put the engine back in, and the motor is so tight it cannot be turned by hand or the starter motor.

What do i do now? should i tow it?

[Cubes]

Battery not dead?

The crank measured? I haven't built a motor myself but I was under the impression you needed some plasti guage the rods and the crank to determine what size bearings to be used.

[SteveL]

You should not try any further to turn the motor over, by whatever means - you'll only do damage. It will be a case of unbolting the crank and doing it by the numbers......measure all the bearing clearances using something like plasti-gauge. Well, thats what I'd do. Measuring the bearing clearances directly is the only way to be sure, AFAIC.

Another possibility is that you have a 'tight' thrust face, have you measured the end float on the crank ??

[SXR]

Just got the rb20 a new crank, main and big end bearings. The crank was measured at an engine shop, and the correct grade bearings were then installed going by the crank size.

Just put the engine back in, and the motor is so tight it cannot be turned by hand or the starter motor.

What do i do now? should i tow it?

If you can't turn by hand, theres something wrong.

Didn't you or they try turning the crank before installed into the car?

Might also wanna check the valve timing.

[HRthirtyone]

You should not try any further to turn the motor over, by whatever means - you'll only do damage. It will be a case of unbolting the crank and doing it by the numbers......measure all the bearing clearances using something like plasti-gauge. Well, thats what I'd do. Measuring the bearing clearances directly is the only way to be sure, AFAIC.

Another possibility is that you have a 'tight' thrust face, have you measured the end float on the crank ??

i am quite confident that the bearings are the correct size, crank was measured to see if it was out of round etc, and the plasti-guage was used. there was bugger all end float, but it wasnt measured.........

[HRthirtyone]

also, forgot to mention, i had it running for a minute or two, then it stalled and now its siezed. but it was very tight before also. VALVE timing also checked.

Edited September 30, 2006 by HRthirtyone

[`nigno]

Dude... take it apart, and double check everything. If you try anything dodgy to save yourself ripping it out and opening it up, your jsut gonna break something cost yourself mroe money and be back at square 1.

Unfortunately its the only way to be sure in a case like this.

[RB30-POWER]

remove the plugs and put it in neutral if you can't turn the engine by hand easily, something is way off.

[HRthirtyone]

yea i tried that hey!

[dangerman4]

also, forgot to mention, i had it running for a minute or two, then it stalled and now its siezed. but it was very tight before also. VALVE timing also checked.

when it started the first time how much oil pressure did it have ?

ANY ?

[SXR]

that was my next question.....oil pressure

have you checked the oil pump when it was off

[SteveL]

also, forgot to mention, i had it running for a minute or two, then it stalled and now its siezed. but it was very tight before also. VALVE timing also checked.

Ummm, some pretty important details. Sounds like some clearances were not correct and that, possibly combined with low or no start-up oil pressure has caused a bearing or bearings to pick-up. I really don't think you've got any choice but to at least drop the sump and check the crank and bearings. Should be no nead to remove the head. Of course all this assumes that something really unuasual hasn't occured (eg seized starter....extremely unlikely).

[kwazza11]

And did you use heaps of assembly lube? could be a bearing has nipped up, did it run rough when it was first started?

[HRthirtyone]

didnt check the oil pressure when it started, because i started it outside the car, and it was running rough, i just checked all the injector plugs and coil pack plugs, then it came good, idled on all six for about 30 sec. then stalled. Oh, plenty of assembly lube, and it has a new starter motor that is all good

Edited September 30, 2006 by HRthirtyone

[dangerman4]

didnt check the oil pressure when it started, because i started it outside the car, and it was running rough, i just checked all the injector plugs and coil pack plugs, then it came good, idled on all six for about 30 sec. then stalled. Oh, plenty of assembly lube, and it has a new starter motor that is all good

the ONLY thing you need to worry about when first starting a fresh rebuild is oil pressure.

when you have the engine on a engine stand, and before you bolt the sump on, pour some oil into the pickup "with the motor upside down" and get a friend to slowly turn the crank around so the oil pump can

a: prime itself

b: pump oil to the crank and other essential areas that oil is required.

it only takes a couple of minutes but you will never have any oil pressure issues on first startup.

I hate to say it but its spanner time for you.

[HRthirtyone]

yes i will pull it out again..... was hoping it could be something simple, but all well im getting good at it now, got the last one out in 2hours.

hopefully nothing is damaged.

[dead32]

any sort of death noises b4 it stalled? when rebuilding its important to get ALL measurements cheaked, then as ur instaling pistons once measured, turn the motor over by hand afta each piston is installed, thus making sure that its not excesivly tight, e.g poor thrust face or end cap clearences

[Adriano]

big end conrod caps could be on backwards

[Cubes]

Mine with the plugs in was pretty difficult to spin over by hand.. But you could feel it was free until one of the pistons came up on its compression stroke.

The RB20 that came out all though it still had ~145psi in all cylinders was very very free even on its compression stroke.

[GTRNUR]

A little sideways on the topic but is there an engine building thread that has all the obvious things to check in it like:

Bearing clearance's and end float clearances

All bolt torque specs and torque orders for the main and head bolts

Tricks for pre-oiling

Startup check lists and cam/lifter wear-in procedure

Assembly tricks like vasoline in the oil pump

Just an idea, but it would make a good sticky thread for those that build engines but would like all the data available on the one page.

Cheers,

Ian